36 V. S. BU?vEATJ OP FISHERIES. 



Table 14. — Wearing qualify of cotton lines exposed to sea water, Woods Hole, Mass. 



Symbol and treatment. 



Unex- 



Number of months exposed. 



Number of strokes. 



A— Not treated 



L — Dutch method 



Q— Copper paint No. 1 



R — Copper paint No. 2 



X — Petroleimi product No. 2 



Y — Copper oleate 15 per cent, benzol 35 per cent, coal tar 



50 per cent 



Z — Copper oleate followed by coal tar 



AA — Copper oleate, 15 per cent in gasoline 



23.9 

 35.6 

 14.8 

 (") 



130.3 

 157.0 

 99.8 



1 Average of 100 tests; every other figure in this table is the average of SO tests. 

 * Line v.'as disintegrated and gone. 



It has been noticed that, with respect to tensile strength and 

 flexibility, the copper paints and the tar-copper-oleate mixtures run 

 ''neck and neck." They differ widely, however, when their wearing 

 quality is measured. The tar-copper-oleate mixtures, Y and Z, lead 

 the entire series in this respect, while the copper paints, Q and R, 

 take last place, as they did in the other series. This might be ex- 

 pected, since copper paint makes the lines harsh, and copper oleate, 

 on the other hand, is smooth or waxy in consistency. Next to the 

 tar and copper mixture is copper oleate alone, AA, then the Dutch 

 method, L, which comes low in the series, because it, too, makes the 

 lines to which it is applied harsh. The petroleum product No. 2, 

 designated X, is here again very low, running only a little better 

 than the white line, A, upon exposure in sea water. 



TESTS WITH LINEN LINES. 



MATERIALS TESTED. 



Besides the tests with cotton lines at Woods Hole, just described, 

 there were also conducted some tests of linen lines. As before, 10-ply 

 linen, such as is used in salmon gill netting, was used. The lines 

 were prepared and placed in the water along with the cotton lines on 

 June 9, 1922, and samples were removed after the first, second, and 

 third months, the test running in tliis case only three months. Linen 

 lines are in practice of course never exposed continuously in the water. 

 For purposes of experiment, however, it seemed that the effects of 

 the preservatives could be brought out more certainly in this way, 

 without the possible entrance of other complicating factors, if inter- 

 mittent exposure had been attempted. Since linen lines do not wear 

 at all well on the wearing-test machine and the preservatives applied 

 to it increase stiffness very little, tests of these two factors were 

 omitted, and only the tensile strength, shrinkage, and increase in 

 weight were determined. 



The preservatives and preservative methods tested were Dutch 

 method, W; petroleum product No. 2, BB; and copper oleate, CC. 

 Untreated linen line, T, was used as control. 



